两相牵引供电系统电能质量有源综合治理技术研究

Comprehensive Active Power Quality Compensation Technology for Two Phase Traction Power Supply System

为解决高速和重载机车给两相供电的牵引变电所带来的负序问题,并兼顾治理谐波和补偿无功功率,考虑到模块级联逆变器无需升压变压器即可直接在中、高电压下应用的优势,提出一种由半桥模块级联组成的铁路用多电平功率调节器,由其组成的两个逆变器可实现两个单相绕组间有功功率的传递。通过合适的功率转换可消除或减少高压系统的负序电流,并补偿各逆变器所连接供电臂的谐波和无功功率。由于逆变器直流侧电压高、电流小,该种方式可避免直流侧大电流带来的散热等难题。本文以采用Scott接线变压器的牵引变电所为背景,对该功率调节系统的运行原理、有功功率、无功功率及谐波的检测和控制进行分析,并搭建一台5电平的模拟样机,实验结果验证了该方法具有可行性和有效性。

In order to solve the negative sequence current problem caused by high-speed and heavy-load locomotives for two phase traction power supply systems and to surpress harmonics and compensate reactive power,considering the advantage of a Modular Multilevel Converter （MMC） able to be directly applied in middle and high voltage systems without the need for an input transformer,the multilevel railway static power conditioner （MRPC） of half bridge modules-cascaded type was put forward,which consisted of two back-to-back power converters to achieve two phase transmission of active power.Appropriate power conversion eliminated or reduced negative sequence currents in the high voltage system and compensated the reactive power and harmonics in the feeding lines that connected to the converters.The presence of high voltage and small current on the DC side of the converter avoided the difficulty of heat dissipation caused by large direct currents.In the context of a traction substation installed with the Scott transformer,the structure,the operating principle and detection and control of active power,reactive power and harmonics of the MRPC system were analyzed.A five-level prototype was established.The effectiveness and feasibility of the proposed MRPC system was proved by experiment results.